public class HelloWorld {
    public static void main(String[] args) {
        int a = 10;
        int b = 20;
        int c;

        c = a;
        a = b;
        b = c;

        System.out.println("变量a=" + a);
        System.out.println("变量b=" + b);

        int i = 10;
        byte j = 20;
        int k = j + i;

    }
}
